Push button electric switch



Patented Mar. 28, 1933 PATENT OFFICE MACKWORTH G. BEES, DETROIT,MICHIGAN PUSH BUTTON ELECTRIC SWITCH .Application :tiled February 6,1930. Serial No. 426,283.

The present invention pertains to a no vel switch 4oi.: the push buttontype for controlling machinery or other electrical apparatus.

In the use of such switches forcontrolling machines in the industry,considerable trouble results from the entrance of particles of dust anddirt around the push button into the bodyv of the switch where itinterferes with the working parts. The principal object of the inventionis to provide a switch which obviates this dii'icult-y.

In the accomplishment of this object, the push button is snuglysurrounded by a flexible gasket extending across the switch hous- 5 ing.The button is preferably formed with a head on the outward side of thegasket and surrounded by a spring which holds the gasket rmly againstthe head. l

Another object of the invention is to insure proper engagement betweenthe relatively movable contacts of the switch when contact is desired.rlhe housing carries a pair of fixed 'contacts cngageable, by a movablecontact mounted on the` push button. The movable contact is in thenature of a disk loosely mounted on the push button and placed undertension towards the fixed contacts by means of a spring. he loosenesspermits and the 3,) spring tension compels shitting of the loose contactto the relative position necessary for perfect engagement with the fixedcontacts, and by virtue oi this construction the accurate setting oradjusting of the switch members in assembly is rendered unnecessary. yFurthermore, the spring limits the pressure that may be applied to thefixed contacts, so that the latter cannot be bent by excessive pressureon the push button.

example in the following description and in the accompanying drawing, inwhich- .Figure 1 is a bottom plan view of the device, with the lowergasket partly broken away;

Fig. ure 1;

Fig. 3 is a side elevation of the switch attached toa box or mountingwhich is illustrated in section;

2 is a section on kthe line 2-2 of Fig- The invention is fully disclosedby way of' Fig. 4 is a front elevation of the switch, corresponding toFigure 3; and

Fig. 5 is a section on the line 5-5 of Figure 4.

Reference to these views will now be made f' by use of like characterswhich are employed to designate corresponding parts throughout.

The device is built in a housing 1 of suitable insulating material whichmay be molded or otherwise formed as desired. The lateral wall 2 of thehousing is\inclined outwardly and formed with a flange 3 depending fromits upper edge. At the bottom of the housing is formed an integral bossor well 4 adjacent c5 which is a similar construction in the nature of acurved wall 5, for a purpose which will presently appear.

To the base or bottom of the housing 1 are attached two fixed contacts 6and 7 which are 70 bent in such a manner as to extend over the lower endof the boss 4 as clearly shown in Figures 1, 2 and 3. These members areheld against the bottom of the housing 1 by means of binding posts 8,the heads 9 of which are 75 molded in the bottom of the housing as shownin Figure 2. lThe member 7 has an extension l0 which enters the areaenclosed by the curved wall 5 and there functions also as a contact foranother switch unit as will presently appear. To the bottom of thehousing is attached still another fixed contact member l1 by means of abinding post 12 and extending into the enclosure within the wall 5.

A push button 13 is slidably mounted in the 85 housing 1, through thebottom thereof, and is equipped with a head 14 at its upper end. Thelower end l5 of the push button is reduced and extends into the well 4where it is loosely 'surrounded by a movable contact 90 disk 16 adaptedto engage the contacts 6 and 7 The shoulder formedbetween the body ofthe push button 13 and the reduced end l5 is engaged by a washer 17surrounding the reduced end. The washer is in turn engaged by a conicalcoiled spring 18 surrounding the reduced end and bearing against l oneside of the contact 16 which is held at its other side by a cotter pin19 passed through the reduced end 15.

The housing is -completed by a cover 2O which fits over the fiange 3 andis suitably apertured at 21 to receive the head 14. A flexiblev 'gasket22 for shielding the switch mechanism from dust and dirt has its edgeclamped between the housing proper and the cover and snugly fits aroundthe push button directly beneath the head 14 as clearly shown in Figure2. The push button is also surrounded by a washer 23 inwardly of` thegasket and finally by another conical coiled spring 24 between thewasher and the base 1 of the housing, whereby' to press the washer andgasket against the head 14 and normally move the button 13 outwardly.The cover is secured to the housing proper by screws 25 and nuts 26 asshown more clearlyl in Figure 5. Longer screws 27 are also passedthrough the cover and housing for securing the switch structure to a box28 as illustrated in Figure 3. In this connection the gasket 29 is ap-vplied to the bottom of the housing 1 around the walls 4 and 5 andpositioned to seal against the outer edge of the box 28 as also shown inFigure 3.

Another push button 30 generally similar to that described isslidably'mounted inthe housing 1 and cover 22 for coperation with thecontacts 10 and 11. The reduced inner end .31 of this member may consistof met'al suitably attached'to the body portion cf the button which ispreferably of a molded in.

sulating material. On the reduced end is loosely mounted a contact disk32 adapted normally to bridge the contacts 10 and 11 as will presentlyappear. A spacer A33 is preferably fitted over the reduced end 31between the disk and the molded body portion of the push button. Thestem of the push button passes snugly through the gasket 22 directlybeneath the button head 34 in the manner already described, and beneaththe head is a washer 35 engaging the innerlside of the gasket. A conicalcoil' spring 36 surrounds Athe push button between the washer 35 and thebase of the housing 1, thereby pressing the washer and gasket againstthe head 34 and holding the contact 32 in engagement with the fixedcontacts 10 and 11 as illustrated.

The walls 4 and 5 serve as guards to prevent wiring within the box 28from taking a position between the fixed and movable contacts Where itwould interfere with the engagement of the contacts.

The dual switch illustrated is intended for y use in conjunction with arelay system, al-

though either of the units may be used separately forthe making andbreaking of a circuit. In a relay system, however, the contacts 7 and 10may be attached to a common conductor at their common binding post 8,while separate conductors may be attached to the remaining binding post8 and the'post 12. The contacts 6 and 7 are normally spaced from eachother, since the spring 24 tends "of the switch structure.

to retract the push button 13 and the movable contact 16 from thecontacts 6 and 7 l The other movable Contact 32 however is in engagementwith the fixed contacts 10 and 11 as already stated.

As an illustration of the use ofthe switch, the contacts 6 and 7 may becomprised in a circuit controlling a relay for making and breaking thecircuit containing the contacts 10 and 11, the latter circuit alsocontrolling a motor or machine. On compression of the push button 13 tobridge the contacts 6 and T, the first circuit is closed to operate therelay which closes the circuit of the contacts 10 and 11 of the machine.The button 13 may then be released to break the first circuit butvwithout interferin(Y with the second circuit. When it is desired tobreak the main circuit, the push button 30 is depressed to separate .thecontact 32 from the contacts 10 and 11. Accordingly, the exposed heads14 and 34 of the push buttons are labled Start and Stop respectively asAshown in Figure 4.

Due to the loose mounting of the movable contacts 16 and 32 and .thespring tension thereon in the direction towards the fixed contacts, themovable contacts will at all times bear firmly against the fixedcontacts, thereby removing the necessity of accurate setting, tting andaligning the various parts This tension is applied to the disk 16 by thespring 18 and vto the disk 32 by the spring 36. After engagement of thefixed contacts 6 and 7 by the adjacent movable Contact l16, continueddepression' of the push button 13 results merely in a sliding movementof the button relativelyto the contact 16 surrounding it, the lattercontact being held against the adjacent fixed contacts by the spring 18.It willA be evident that the spring mounting of the contact 16 preventsbending of the contacts 6 and 7 under excessive pressure on the pushbutton 13.

rEhe several springs are so formed as to flatten oncompression, with thecoils nested within each other. It is obvious that due to suchconstruction, greater tension may be developed in a spring of given sizethan if the spring were merely cylindrical.

Although a specific embodiment'bfj the invention has been illustratedand described, it will be understood that various alterations in thedetails of construction may be made without departing from the scope ofthe invention, as indicated by the appended claims. "J

What I claim is:

1. In a switch, a housing having a bottom wall, a pair of fixed contactscarried by-said housing beneath said wall, a headed push button having asliding fit in said housing and wall, a movable contact carried by said.button and adapted to engage said xed contacts, a asket snuglysurrounding said push button etween said head and wall, a washer looselysurrounding said push button be neath said wall, a compressed springsurrounding said push button between said wall and gasket, anothercompressed spring surrounding said ush button between said movablecontact an washer, whereby said sprin s press said gasket and washerrespective y against said head and wall. v

2. In a switch, a housing having a bottom wall, a pair of fixed contactscarrled by said housing. beneath said wall, a head push button having asliding fit in said housing and wall, a movable contact carried by saidbutton and adapted to engage said Afixed contacts, a gasket snuglysurrounding said push button between said head and wall, a washerloosely surrounding said push button beneath said wall, a compressedconical coiled spring surrounding said push button between said wall andgasket, another compressed conical coiled sprln surrounding said pushbut' ton between sai movable contact and washer, whereby said springspress saidgasket and washer respectivel against said head and wall, saidsprings ein adapted to be compressed into a substantially fiatcondition. ,30 In .testimony whereof I aix my signature.

MACK'WORTH G. REEs.

